As electrostatic discharge (ESD) problems are encountered in a growing number of consumer electronics devices, ESD protection devices have also become readily available to offer protection from ESD. ESD is a high-voltage transient with fast rise time and fast decay time. Several thousand volts of ESD with a high rise time may break through the junction layer of protective devices easily and cause damage. ESD surge energy, however may be very small. Although ESD has tens of thousands of volts of amplitude, it lasts only several nanoseconds, and the joule rating may be almost negligible. Therefore, it may not require much energy-handling capability from a protective device.
Hence, taken as a whole, the problem of ESD may lie not in the energy handling, but in the voltage surge. Tens of thousands of volts may cause dielectric breakdown of insulation, puncture a wafer junction, or burn off a tiny trace of a microprocessor circuit. Therefore, protection devices shall be strong enough to meet high-voltage surges.
Transient Voltage Suppression (TVS) diodes, ceramic diodes and zener diodes may be used in ESD protection. TVS diodes, also known as avalanche breakdown diodes, may have several advantages in ESD suppression, such as lower clamping ratio and stronger resistance to surges, over ceramic capacitors and zener diodes.
TVS diodes may be available in small packages which may be good for use in slim handheld devices. However, an issue with the small packages may be such that the small packages may accommodate small dies but may not accommodate big, multiple or stacked dies. Because of the die limitation, ESD performance may be correspondingly limited.
Therefore, there is a need for a die package which may accommodate larger dies to obtain better ESD performance.